It is unclear for now just what impact May’s announcement for land releases and an extra £2bn for affordable housing may have. After all, the UK’s housing stock is valued at close to £7 trillion. But her announcement comes after London real estate prices registered their biggest fall in a decade, stoking expectations for further drops in real estate prices.

But what would falling house prices mean for Britain? How might it affect employment, household consumption, investment, the Government deficit and, critically, the UK current account – the net measure of cash flows in and out of the economy.

The greater fool

Brexit and associated uncertainty about the future of the UK financial sector are making real estate investors, home buyers and households more cautious. One of the things that has fuelled London real-estate prices over the years is the “greater fool” mechanism. Buyers knew that a property was expensive, and perhaps ridiculously expensive, but they counted on the fact that they could sell it later to a “greater fool” at an even higher price, for a handsome profit.

That phenomenon was perhaps best displayed in the first recorded crisis in free markets. Tulip mania in 17th century Holland built to a crescendo which saw single, rare tulip bulbs change hands for extraordinary sums. Historian Mike Dash has described it as enough to “purchase one of the grandest homes on the most fashionable canal in Amsterdam for cash, complete with a coach house and an 80 foot garden”.

As tulip mania went on to show, however, if prices show indications of a fall, the upward trend reverses violently. If property investors become skittish, they will try to sell before prices fall further, and all of them at the same time. Property values built over decades could collapse within months: the expectation of falling prices causes the falling prices.

This mechanism is a real danger in London which relies heavily on local and international investors who view properties not as a home but as a commodity, readily sold to maximise profit. In 2013 alone, international investors accounted for 82 per cent of London property activity.

Falling for it

However, most properties in the UK still belong to households. Families, by and large, don’t need to sell. So what would falling property prices mean for them?

First, many pension funds and investment bonds rely on UK property to generate income for their beneficiaries. Second, we have what economists call the wealth effect.

House prices rise at fastest pace in eight months

Economists have long associated consumers’ perceived real estate wealth with spending behaviour: if you believe your house is worth a lot, you feel financially secure. And then you allow yourself to save less and spend more. Just consider the rising number of people who plan to subsidise their retirement with wealth generated by their homes.

If their assumed valuations start to look shaky, these people will spend less to build up their savings. The pain would be felt by many: about 64 per cent of households in England are owner-occupiers.

Ripple effects

The climate of economic uncertainty, reduced consumption and falling real estate values brings an additional problem for the UK. Britain has long had a trade deficit, but it has also benefited from positive foreign direct investment.

The current account itself has been in the red for nearly 20 years now but the hundreds of billions of inward foreign investment channelled to UK property over the same period meant that this deficit remained manageable – just about.

According to the Bank of England, overseas companies have accounted for roughly half of all UK commercial real estate transactions since 2013. If international investors expect prices to fall in any sustained way, the inflow of money would stop and many would sell up. Why buy or hold an asset just at the start of what might be a long decline?

This would not only put pressure on real estate prices but would affect UK GDP, reduce government revenues and worsen the UK current account position. The credit rating of the UK would come under more pressure, and trillions of UK government debt would cost more to refinance. Then the UK government deficit would deteriorate further, taxes might rise to cover for this and the domino effect would be in full cry, spreading to all sectors of the economy, similar to events in Greece.

Policy plays

Real estate values are critical to the UK’s prosperity. Households, pension funds and businesses have invested heavily; most of the country has, in one way or another, skin in this game. Britain may need to wean itself of its property addiction, but it also needs to sustain confidence in the single asset class that counts for almost two thirds of its wealth.

Schemes like Help To Buy might soon trigger a recession

It is deeply difficult politically to sell that story, however, when the understandable clamour is to make housing more affordable. In a move designed to win over younger voters, May has imposed punitive taxation on landlords, cutting one of the life-lines of UK real estate and driving many out of the market. The new measures announced at the Conservative party conference apply further pressure.

May is desperate for a positive message but the implications of targeting the real estate market right now are huge. Britain’s Brexit fumbling is already failing to inspire confidence. The fear has always been that Brexit would spark a period of stagnation, but the danger of deeper, more accelerated damage now seems real, and the potential effect on property values and the economy stark.

The UK government should act decisively. This would require the continuation of loose monetary policy, a reinstatement of tax incentives for real estate investment and, of course, a real plan for Brexit and the future of London’s financial services industry.

Alexander Tziamalis is a senior lecturer (associate professor) in economics and a consultant at Sheffield Hallam University. This piece originally appeared on the Conversation